From the related art, a large number of pedicle screws for fixation of the spinal column are already known; these known pedicle screws have the advantage that the individual pedicle screw can be attached to or removed from the longitudinal bar at any time without having to dismantle the entire fixation system. Such a pedicle screw is known from European Patent No. 330, 881 B, for example.
The disadvantage of this and similar pedicle screws is the relatively complicated locking mechanisms for securing the longitudinal bar inserted into the open pedicle screw head. Furthermore, in most cases the head of the screw can be aligned with the position of the longitudinal bar only to a limited extent, necessitating complicated bending of the longitudinal bar to correct the angle.